This invention relates to a method of verifying the identity of a pipeline at one location as being the same as a pipeline at another location.
In pipeline work, identification of pipelines already in place for a period of time is increasingly becoming a more difficult problem despite the use of color codings, maps, etc. In large part, this increase in difficulty is due to the ever increasing number of lines being laid, more activity on the lines, and more emphasis being placed on environmental concerns. For example, when a worker digs down into a pipeline right of way for natural gas pipelines, he is often confronted with several pipelines. How is he to be sure which one of the several lines is the one which has been purged of explosive gas before he cuts into it with his cutting torch. This uncertainty of identification exists even of pipelines above ground where tracing would seem very easy. But, for example, where the location of work to be carried on a pipeline is miles distant from its source or is in a pipe rack containing several lines, such tracing becomes increasingly difficult. The uncertainty of having the wrong pipe is a very real factor to the worker, or it should be, for there have been many incidents wherein serious injuries and fatalities have occurred.
Several pipeline location devices have been tried but due to pipeline crossings and turnings and due to the presence of older and newer pipelines in the same vicinity, often known but also often unknown, these location devices have not proven as satisfactory as one would desire.
Hence it would be highly advantageous to have a method of positive pipeline identification. The present invention achieves this.